1. Field of the Invention
The field of invention is human powered watercraft. In the field of human powered watercraft, the body boarder who surfs the ocean waves, the diver who paddles from the beach to the kelp beds, the racer of human powered boats, and even that forlorn recreational boater whose vessel has sunken beneath him, all try to power themselves across the water by such meager resources as their own human engine and athletic grace allow. Whether to catch a wave, to get to a dive spot, to set a world human powered watercraft speed record, or simply to return oneself to the haven of land, each wants to optimally apply their human power and speed themselves and their craft thru the water. Therefore, in this context, power and speed properly applied can save a life, can set a personal best or even world speed record, can give access to hitherto inaccessible dive spots, and also, can yield a best wave ever ridden. A new human powered watercraft that enables the boater overboard to self rescue, that helps the body boarder to get more and better waves, that offers the racer a chance at a personal best, and that gets the diver to and from dive spots previously difficult to reach is a worthy invention. The new human powered watercraft and propulsion system of this invention will be welcomed by the community of watermen and women, beachgoers, cross-training athletes and the boating community and will be advantageously marketable in a hard or soft shelled surfboard embodiment in a broad niche centered between existing low end manufactured body boards and high dollar custom shaped surf boards. The broadness of the market niche will profitably encompass that of kayaks and racing shells, yet due to its inherent simplicity, the invention is readily adaptable to the scale economies of pool recreation devices and hobbyist's radio control models. Economically manufacture-able, compact, convenient, light weight, and fast, the invention ideally spans the product markets of board wave-riding devices, boater self-rescue craft, paddle boards for near shore divers, and speed record capable human powered watercraft.
2. Description of the Related Art
Krah, U.S. Pat. No. 7,232,350 propels a watercraft by a standing user thrusting a handle of a bar up and down, the bar connecting to a dagger board with a horizontal fin, the fin when not propelling stores in a recess in the watercraft. The invention does not allow leg powered propulsion from an essentially kneeling position as does the invention of this application.
Maisonneuve, U.S. Pat. No. 4,464,126 propels a surfboard by thrusting a lever forward and aft from a sitting position to drive a lower fin up and down. The system does not allow the surfer to move about the surfboard and the lower keel structure causes yaw instability with forward motion.
Chen, U.S. Pat. No. 6,468,118 propels a surfboard thru two foot treadles with an up and down leg motion deflecting separate fins. This system attaches the user to the board which can be dangerous when the board rolls over, somewhat entrapping the user.
Momot, U.S. Pat. No. 4,968,273 propels a surfboard with a single treadle driven fin using weight shifting forward and aft to propel the board. The system has a great deal of drag surface offered to the water, does not stow and so is constantly dragging down board speed.
Domancic, U.S. Pat. No. 5,549,491 propels a surfboard or boat by a single treadle driving two fins by a lateral, side to side weight shift. This motion is particularly destabilizing to a surfboard rider as the board is narrow and least stable laterally.
Malm, U.S. Pat. No. 3,377,977 propels a surfboard by a sculling-sweeping motion of a centrally pivoted oar. The lateral side to side motion of this system destabilizes the surfboard.
Ueno, U.S. Pat. No. 4,936,802 propels a surfboard by a single foot treadle driving a vertical fin to sweep laterally back and forth. The fin motion causes the boat or board to slough sideward without the stabilizing presence of a keel.
Ketterman, U.S. Pat. No. 6,022,249 propels a kayak via foot treadles that drive two flexible fins in opposing directions about the keel of the boat. The system is heavy and complex while also being subject to damage during beaching of the vessel as the fins are most exposed below the keel and users frequently forget to stow the system.
Puzey, U.S. Pat. No. 6,099,369 propels a tricycle hydrofoil by a bounding up and down motion of the user. The system suffers from the inability to start from the water and is unstable in yaw when in following seas.
Shiraki, U.S. Pat. No. 5,194,024 propels a surfboard via a pedal-crank propeller system operated by a recumbent seated rider. This and all recumbent systems impede the operator's ability to react to perturbing waves by limiting all but the users head from counteraction. As with other pedal and crank systems, the device is most efficient when one is clipped in and as stated previously, this makes emergency egress problematic and failed attempts to egress possibly fatal.
Gander, U.S. Pat. No. 4,304,555 propels a float device by a foot operated bell crank driven fish-fin. Absent a keel, the vehicle is unstable in yaw when propelled thusly.
Han, U.S. Pat. No. 6,033,276 propels a surfboard via a bell crank foot operated fish fin. The system causes the board to yaw during operation.